Polymerization vessel having readily removable working parts

ABSTRACT

A polymer finisher having all of the working components designed to be preassembled as a unit apart from the finisher casing and to be quickly and readily installable within or removable from the casing in an arrangement providing reduced vibration and improved thermal conditions. When the preassembled unit is slid into the casing, the remote end of the stator-supporting rail fits into a pilot hole near the remote end of the casing. The nearer end of the rail is then attached to the nearer end of the casing. The stator members are thus prevented from rotating in the assembled reaction vessel, although they are supported on the rotor during assembly and disassembly.

United States Patent lnventor Joseph M. McCown Pensacola, Fla.

Appl. No. 13,491

Filed Feb. 24, 1970 Patented Jan. 1 l, 1972 Assignee Monsanto Company 1 St. Louis, Mo.

lm.CI com/9s, BOljl/OO FieldofSearch 23/285,

' Primary Examiner-James H. Tayman, .lr.

AttorneysStanley M. Tarter, Neal E. Willis and Elmer .l.

Fischer ABSTRACT: A polymer finisher having all of the working components designed to be preassembled as a unit apart from the finisher casing and to be quickly and readily installable within or removable from the casing in an arrangement providing reduced vibration and improved thermal conditions. When the preassembled unit is slid into the casing, the remote end of the stator-supporting rail fits into a pilot hole near the remote end of the casing. The nearer end of the rail is then attached to the nearer end of the casing. The stator members are thus prevented from rotating in the assembled reaction vessel, although they are supported on the rotor during assembly and disassembly.

PATENTED JAN] 1 I972 SHEET 1 [IF 3 JOSEPH M. McCOWN AGENT PATENTEB JAN] 1 m2 SHEET 2 0F 3 333 1 INVENTOR. JOSEPH M. MCCOWN AGENT PATENIED mu 1 I972 SHEET 3 BF 3 FIG. 5,

4 INVENTOR.

JOSEPH M. McCOWN AGENT POLYMERIZATION VESSEL HAVING READILY REMOVABLE WORKING PARTS BACKGROUND OF THE INVENTION Polymer finishers are processing vessels employed to devolatilize and polymerize polyamides, polyesters and like materials. A common disadvantage encountered in operating conventional finishers is the relatively rapid accumulation of degradable polymer, gel and contaminate. From these accumulations emanate many problems including disassembling, cleaning, reconditioning and assembling the finishers. These are costly, time consuming, and interrupting problems. As a consequence, finishers are continually being modified to yield less carbonized residue and to improve them structurally to shorten overhaul periods.

It is the object of this invention to provide a finisher of the type disclosed in U.S. Pat. No. 3,476,523 with improvements providing more expeditious assembly and disassembly procedures and more efficient mechanical and thermal operating conditions that effect a better product.

SUMMARY OF THE INVENTION The finisher embodying the invention comprises a jacketed vessel or casing having a horizontally disposed journaled drive shaft with a plurality of spaced rotors each mounted in row alignment along the length thereof. The rotors each comprise concentric cylinders that are wiped by fixed blades positioned adjacent the cylinder walls. The blades are carried on rods journaled on the drive shaft and pivoted rotatably on a rail. The rail is constructed to be easily attached to or removed from brackets or flanges provided on the inner wall of the jacketed casing.

The drive shaft, cylinders, rods, wipers, and rail may be preassembled as a unit and readily installed or removed from the vessel. The components are arranged to minimize vibration, to provide more uniform thermal control, and to strengthen the load bearing capability of the components.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. I is a side elevation view of the finisher with portions broken away,

FIGS. 2-4 are perspective views of the flange-fastening arrangement for the wiper assemblies.

FIG. 5 is an elevation view illustrating a wiper assembly with portions of the adjacent components, and

FIG. 6 is a top view of thejoumal rod.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to FIG. 1 in the drawings, the improved finisher comprises a horizontally extending vessel or casing 2, preferably with a surrounding thermal jacket 4, defining a thermal chamber therebetween. Dowtherm is a common agent charged to the thermal chambers of finishers. Casing 2 has a polymer inlet 6, a polymer discharge outlet 8 and a vapor exhaust port 10. Temperature and pressure gauges (not shown) are used as needed. Each end of casing 2 is provided with a hub I2 and one of the ends is sectioned to provide a removable end cover 14 that is sealingly bolted to casing 2. A drive shaft 16 extends longitudinally through casing 2 and hubs I2, and is driven by a motor 18. Hubs 12 include a packing gland. Shaft 16 is journaled in conventional pillow blocks 17.

A plurality of spaced rotor units 20 are mounted fixedly along the length of shaft 16. As shown in FIGS. 1 and 5, each rotor unit 20 is a composite of a plurality of cylinders 22 having different radii arranged concentrically on a webbed wheel 24 keyed to drive shaft 16. Cylinders 22 are secured in slots at opposed sides of each webbed wheel 24. Preferably, cylinders 22 have perforations 26 (FIG. I) to increase thin filming ofa polymer and to provide for passage of gases.

As best shown in FIGS. 1 and 5, stator blades or fingers 28 extend between adjacent cylinders 22. The polymer trailing from cylinders 22 and sagging through perforations 26 is pulled therefrom by stator blades 28 in the form of strings and films. This increases the exposed polymer surface area, as disclosed in U.S. Pat. No. 3,476,523. Stator blades 28 are mounted on suspension rods 30 and project therefrom into close adjacency of the inner and outer cylinder 22 surfaces. Rods 30 are positioned between and at the ends of rotor units 20. The upper end of each rod 30 is arranged to pivot slidably about horizontal rail 32.

The lower end of each rod 30 (FIG. 5) partially surrounds shaft 16, and has ajoumal or bearing cap 34 secured thereto by bolts. Cap 34 retains the lower half of a bearing, the upper half being retained in a respective rod journal end. The upper ends of each rod 30 are pivotally mounted on rail 32 by eye 36.

In the preferred embodiment, each cylinder 22 is wiped exteriorly and interiorly by blades 28. The blades 28 that wipe each innermost cylinder 22 are mounted on the bearing caps 34. The latter are also, preferably, provided with blades 28 for wiping the drive shaft 16, FIG. 5.

Blades 28 have a curvature complementary to the walls of cylinders 22 and have a twist or rake to provide a helical flute or channel for controlling the flow of polymer. Some of the blades 28 may have more rake than others and some may be shorter than others as desired.

As shown in FIGS. 1 and 4, the end of rail 32 remote from cover 14 has a smaller diameter end 38 that fits into a socket or pilot hole 40 in a bracket or flange 42 that is bolted to the inner wall of casing 2. At its opposite end 44 (FIGS. 1 and 2), rail 32 is threaded and has adjusting means as locknuts 46 to compensate for excess clearances. Flange 48 is suspended within vessel 2, and supports end 44 by means of a threaded plate 50. Rail 32, between flanges 42 and 48, is supported by flanges 52 (FIG. 3) bolted to the inner casing wall of vessel 2. Flanges 52 have curved surfaces engaging with collars 54 positioned astride of each rod 30. A further collar 54 positions rail 32 at the pilot or small diameter end 38 of rail 32 (FIG. 4).

The following description indicates the ease of assembly and disassembly of the finisher. In assembly, the suspension rods 30 and rotors 20 are positioned, alternately, on the drive shaft 12 as shown in FIGS. I and 5. Rail 32 is then threaded through eyes 36 of rods 30 and collars 54 and the latter are positioned and tightened on the rail 32. With the end lid or cover 14 removed, the assembled working parts are lifted into casing 2. The pilot end 38 (FIGS. 1 and 4) of rail 32 is piloted into hole 40 of flange 42 until collar 54 contacts flange 42 and. cooperatively, shaft 16 is slid through the hub 12 nearest motor 18. Plate 50 (FIGS. I and 2) having been threaded on rail 32 is then bolted to flange 48. Cover 14 is subsequently bolted sealingly and securely to casing 2.

The finisher can be quickly dismantled by removing cover 14 and unbolting rail 32 at flange 48 (FIG. 2). The inner working components are then removable as a unit, after drive shaft 16 is disconnected from motor 18.

Hubs 12 are preferably located to position drive shaft 16 below the central longitudinal axis of casing 2 so that when rotor units 20 are rotated the outermost cylinders 22-of each unit 20 rotate close to the bottom of the casing 2 while a larger space is provided at the top thereof. Accordingly, gases readily escape and the polymer being processed is lifted from the bottom of the casing 2.

The finisher operates to remove volatile byproducts from condensation polymers. Polymer delivered to the finisher is formed into thin films, rotated and transported by driven rotors 20. The high viscosity polymer clinging to the rotors is wiped therefrom by blades 28 positioned close to the cylinder 22 and shaft 16 walls. The viscous polymer is transported and discharged from outlet 8.

A salient feature of the finisher is its arrangement of parts permitting a quick overhaul to be made as already described. The arrangement of parts also provides advantages in controlling thermal conditions and in controlling vibration. The said cylinders, said stator members being positioned spaced position of rail 32 from the heated wall of the vessel 2 above the normal liquid level in said vessel, said support minimizes the transfer of heat to the rods 30 and blades 28 means comprising: which may cause undesirable heat pockets and encrustation of l. a detachably mounted rail extending within said vessel polymer on the heated parts. The pivotally anchored position 5 and generally parallel to the axis of said shaft, of rods 30 on rail 32 and shaft 16 provides control over the 2. socket means, fixedly mounted inside said vessel at a stresses applied to the wipers by the viscous polymer. position near the other of said end walls, for receiving I claim: and supporting one end of said rail,

1. A polymerizer reactor comprising in combination; 3. detachable means, mounted inside said vessel near said a. a generally horizontally extending shaft rotating about its l0 n Of said walls, for supporting the opposite end of i said rail, and b. means mounted on said shaft for generating a plurality of a plurality of Suspension rods one end of each Said suspension rods being pivotally mounted on said rail, the opposite end of each of said suspension rods being journaled on said shaft, said stator members being mounted on and supported by said suspension rods,

e. means for heating said vessel,

f. means for introducing polymerizable material at one end of said vessel, and 20 g. means for recovering polymerized material at the opposite end of said vessel.

radially spaced cylinders as said shaft rotates,

c. stationary walls defining a vessel, said walls including a generally cylindrical portion between opposed end walls, 15 said portion closely surrounding the lower half of the outermost of said generated cylinders, one of said end walls being detachable,

(I. support means extending from one of said stationary walls and supporting stator members between adjacent cylinders, said stator members extending within and closely adjacent said cylinders over most of the length of 

2. socket means, fixedly mounted inside said vessel at a position near the other of said end walls, for receiving and supporting one end of said rail,
 3. detachable means, mounted inside said vessel near said one of said walls, for supporting the opposite end of said rail, and
 4. a plurality of suspension rods, one end of each said suspension rods being pivotally mounted on said rail, the opposite end of each of said suspension rods being journaled on said shaft, said stator members being mounted on and supported by said suspension rods, e. means for heating said vessel, f. means for introducing polymerizable material at one end of said vessel, and g. means for recovering polymerized material at the opposite end of said vessel. 